Fluid handling device with radially variable working chambers

ABSTRACT

The two rotors of a fluid handling device, such as a pump-motor hydrostatic transmission, are positioned adjacent each other in axial direction by thrust bearings at the outer axial ends of the rotors so that the confronting inner end faces of the rotors form a fluid filled gap in which spacing means, such as a rotary disc and roller bearings, can be provided.

United States Patent Eickmann [4 Apr. 11, 1972 [54] FLUID HANDLINGDEVICE WITH [56] References Cited %Q Z W0 G UNITED STATES PATENTS2,176,401 10/1939 Johns ..60 53 B 1 Invenwfl farlklllickmflnn, :1Isshiki, Kanagawa- 2,993,339 7/1961 Timms ..60i53 B en, ayama-mac 1,apan d: 2 970 Primary Examiner-Edgar W. Geoghegan [22] me Jan 1Attorney-Michael s. Striker [2]] Appl. No.: 6,668

[57] ABSTRACT [30] Foreign Application Priority Data The two rotors of afluid handling device, such as a pumpmotor hydrostatic transmission, arepositioned adjacent each Jan. 31, Austria ..A other in axial directionthrust i g at the outer axial ends of the rotors so that the confrontinginner end faces of [52] US. Cl ..60/53 B, 91/497 the rotors form a fluidn gap in which Spacing means, Such FISgOIQIS as a rotary disc and tonerbearings can be provided ie 0 Seal-c 12 Claims, 1 Drawing Figure 4 I0222/ ///5 32/ J 4 4 a 22 A 4 7 g a 4 20 39- v' J i M) Vfl 3/ 3 5 iPATENTEDAPR 1 1 I972 3, 654. 7 61 AUXILIARY PUMP I N VEN TOR:

BY KARL E/CKMA/V/V mud/ BACKGROUND OF THE INVENTION The term fluidhandling device with radially variable working chambers" is used in thepresent application to refer to machines with working chambers filledwith fluid, whose volume is cyclically increased or decreased in radialor substantially radial direction by displacement elements, such aspistons or vanes, reciprocating in the working chambers.

Fluid handling devices of this type have been successfully used, buthave not obtained the high efficiency of other transmissions, forexample of a gear transmission. Furthermore, the manufacturing cost isvery high so that use of this type of transmission is not economical.

The main reason for the insufficient efficiency of fluid handlingdevices of this type is the high leakage and friction between surfacesmoving relative to each other, particularly if the relative speed of thecontacting surfaces is high.

SUMMARY OF THE INVENTION It is one object of the invention to overcomethe disadvantages of fluid handling devices of the prior art, and toprovide a fluid handling device, such as a hydrostatic transmission,which has low leakage and friction losses, and consequently a highefficiency.

Another object of the invention is to provide a fluid handling device inwhich cooperating moving surfaces rotate at a low relative speed.

With these objects in view, the present invention provides at least twoaxially adjacent rotors whose axially outer ends are supported by thrustbearings. Between the two rotors control means are provided throughwhich the fluid flows between the working chambers of the rotors. Inaccordance with the invention, the two rotors have inner confrontingcontrol faces through which the fluid flows between the working chambersof the rotors. Due to this arrangement, the control faces which areprovided in prior art constructions at the outer ends of the rotors, areeliminated, and the friction and leakage caused by the same avoided. Inthis manner, the efficiency and output of the machine is increased.

In the preferred embodiment of the invention, a rotary control disc isplaced between the inner confronting control faces of the two rotors,and has at least one opening through which the fluid flows between theworking chamber of the rotors.

The control disc advantageously consists of a different material thanthe rotors so that low friction is obtained between the control faceswhich are in contact.

In accordance with a preferred modification of the invention, thecontrol disc carries rotary coupling means cooperating with the innercontrol faces of the two rotors and rolling on the same so that thecontrol disc rotates at a speed which is intermediate the speeds of thetwo rotors.

Due to the provision of the coupling rollers between the confrontinginner control faces of the two rotors, the relative speed between eachcontrol face and the control disc is halved so that higher rotary speedsof the rotors become possible, while the friction in the fluid filmbetween the contacting surfaces is reduced due to the low relative speedbetween the same. This arrangement is of particular importance for afluid handling device with radially variable working chambers becausethis type of fluid handling device is suitable for high rotary speeds,which is not the case for fluid handling devices with axially variableworking chambers. Due to the arrangement of the invention, the rotors ofthe fluid handling device can rotate at the speed of high speed gasturbines and combustion engines. In a fluid handling device withradially variable working chambers, different axial forces develop ascompared with fluid handling devices in which the working chamber isvariable in axial direction, and consequently the arrangement of thepresent invention is particularly advantageous when applied to fluidhandling devices with radially variable working chambers.

In a preferred embodiment of the invention, a fluid pressure meansacting in axial direction is provided between one end bearing and therespective rotor to urge the same in axial direction so that the widthof the gap betweenthe rotors becomes a minimum, and the cooperatingcontrol faces between the rotors abut each other with the required smallplay even if the bearing means at the ends of the rotors are worn afterprolonged use.

As compared with prior art constructions, the present invention savesseveral control faces and the leakage and friction losses associatedwith the same so that the efficiency of the fluid handling deviceaccording to the invention is high, while the number of parts isreduced.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING A longitudinal sectional viewillustrating a preferred embodiment of the invention as incorporatedinto a hydrostatic or hydrostatic-mechanical transmission.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A stator includes a cylindricalpart 1, two end members 31 and 32, and two end covers 33 and 34. Tworotors 2 and 3 are rotatably mounted in the stator housing supported onball bearings 26 in end members 31 and 32. Roller bearings 27 supportthe hub portion of rotor 3 on the hub portion of rotor 2 so that theaxial length of the device is short. Rotor 2 has a hollow shaft endportion 28, and rotor3 has a hollow shaft end portion 30 projecting outof the cover plates 33 and 34, respectively. A shaft 29 passes throughshaft portions 30 and 28, and through the rotors 2 and 3 so that thedevice has two input shafts 28 and 29 and two output shafts 29 and 30 sothat the latter can be connected by suitable coupling means, not shown,to other apparatus. Sealing means 142 are provided for the shafts.

Rotor 2 has radially variable working chambers 4 in which radiallymovable fluid displacing elements 7 are mounted for reciprocation sothat the volume of working chambers 4 is cyclically reduced andincreased for receiving and discharging fluid, respectively. The fluiddisplacing elements 7 of rotor 2 are pistons which are operated duringrotation of rotor 2 by eccentric means 10, 12, 14, 35 through slideshoes 9 of pistons 7. Instead of cylindrical working chambers 4 andpistons 7, flat working chambers and vanes moving in radial directionmay be provided. This construction is shown for rotor 3 which has radialchambers 5 in which displacing elements including rectangular flat vanes8 and slide shoes 36, 37 are mounted.

Rotor 3 has end walls 21 and cover plates 22 which are part of rotor 3and rotate with the same. A rotary ring 11 runs on ball bearings 15 inan eccentric stator ring 13, and closes the radially extending workingchamber 5, while controlling the radial reciprocating movements of thefluid displacing elements 8, 36, 37.

The vanes and vane chambers of rotor 3 could also be pro vided in rotor2, or rotor 3 could be provided with cylindrical working chambers andpistons as shown for rotor 2.

From each working chamber 4 or 5, a conduit 16 or 17, respectively,extends through a part of the respective rotor 2 and 3 and through oneof first and second confronting control faces 61 and 62. The fluid flowsthrough an opening in a control disc 6 provided in the gap between theconfronting control faces 61 and 62 of rotors 2 and 3. The rotorconduits 16 and 17 have openings in the control faces 61 and 62 and formports in the same. Fluid flows through the rotor conduits 16 and 17 intothe working chambers and out of the same. As indicated by legends, theleft part of the illustrated apparatus, including rotor 2, serves as apump, and the right part, including rotor 3, serves as a hydraulicmotor.

The confronting control faces 61 and 62 are shown to be planar, but canbe spherical or conical.

The confronting inner end faces 61 and 62 of rotors 2 and 3, and theopenings of conduits l6 and 17 in the same form control faces.

The outer ends of the rotors have outer end faces which are supported inaxial direction by thrust or end bearings and 20 which abut the innerend faces of end covers 33 and 34 of the stator to hold rotors 2 and 3,and the spacing control disc 30, in a predetermined axial position.

The provision of a control disc 60 is not absolutely necessary, and in amodified arrangement of the invention, the control faces 61 and 62 arein sliding abutment forming a very narrow fluid filled gap between eachother. When the rotors 2 and 3 rotate at different speeds, theconfronting inner control faces rotate relative to each other while insliding contact.

As compared with the prior art, control faces at the outer end of tworotors are eliminated, together with the leakages and friction caused bythe same. Such leakage and friction losses at the outer ends of therotors substantially reduce efiiciency. The present invention eliminatesleakage losses at the outer ends of the rotors completely, andsubstantially reduces friction losses.

In the prior art construction, the inner control faces also cause greatlosses. In accordance with the prior art, a stationary control body isprovided between confronting inner control faces corresponding tocontrol faces 61 and 62. Since the control body is stationary in theprior art, the relative speed between the rotor controlled faces and thestationary controlled body is very high, causing great friction andleakage. Particularly, at high speeds of the rotors, the friction lossesare extremely high. This is also due to the fact that in the prior arttwo gaps are necessary between the control body and the two controlfaces of the two rotors.

In the simplified arrangement of the invention, not shown, in which thecontrol faces 61 and 62 slide on each other separated only by a thinfilm of fluid, only one control gap is provided so that by this veryfact leakage is reduced. Furthermore, under certain operationalconditions, a great deal of friction is saved in accordance with theinvention, when the two rotors run at high rotary speed, but at equalrotary speeds in the same direction so that there is no relativemovement between control faces 61 and 62 and the thin fluid film in thegap between the same.

A relative movement between control faces 61 and 62 only occurs whenrotors 2 and 3 rotate at different rotary speeds. In the prior art, whena stationary control body is provided between the same, there is arelative speed between each rotor control face and the stationary body,which causes particularly high losses at high rotary speeds of therotors. In the present invention, irrespective of the height of therotary speed of the rotors 2 and 3, only the relative speed between thecontrol faces 61 and 62 determines the friction, which is zero if therotors rotate at the same speeds, even if the speed is very high.Consequently, the apparatus of the invention operates very efficientlyeven at very high rotary speeds, and can be, consequently, used as atransmission for high-speed combustion motors or gas turbines. However,even for low speed drive motors, such as electromotors or diesel motors,the arrangement of the invention operates more efficiently than knownfluid handling devices with radially variable working chambers.

A fluid handling device of the above-described type can only operate ifthe working chambers are always filled with fluid. In accordance withthe invention, the rotor 2, which performs the pumping function in thetransmission is provided with an auxiliary pump or compressor 38 whichis mounted on cover plate 33 in a recess of the same closed by a closure41. The rotary part of the pump 38 is driven by the hub portion of rotor2 so that the fluid flows through an inlet conduit 39 in cover plate 33into pump 38, and through a conduit 40 into one or several workingchambers 4. Check valves, not shown, may be provided in the conduit 40so that the complete filling of the working chambers with fluid isassured.

As compared with the prior art, in which the feeding of the fluid takesplace through stationary parts of the apparatus, the conduit 40 isprovided in a portion of rotor 2, and partly through a hub or shaftportion of the same.

In the illustrated embodiment, the confronting control faces 61 and 62do not slide on each other, but a control disc 60 is positioned in thegap between the same, and spaces the two rotors from each other in axialdirection. Control disc 60 has outer faces which are shown to be planar,but which may be spherical or conical to match corresponding sphericalor conical control faces 61 and 62 of rotors 2 and 3. Conduit portionsor openings pass in axial direction through control disc 60 which atleast partly form portions of the conduits 16 and 17 in rotors 2 and 3which connect the working chambers 4 and 5. It is an advantage of thecontrol disc 60, that it can be made of a smooth material which reducesthe friction between the control disc 60 and the control faces 61 and 62of the two rotors.

In accordance with the invention, control disc 60 carries radiallyprojecting coupling means 18 which include cage means and rollers inrolling contact with control faces 61 and 62. Instead of rollers, gearsmeshing with gear portions on control faces 61 and 62 may be provided.Due to the fact that the rollers roll simultaneously on control faces 61and 62, control disc 60 rotates at an intermediate speed between thespeeds of control faces 61 and 62 and of rotors 2 and 3, respectively.Due to the fact that the relative speed between the engaging controlfaces is halved, the friction is substantially reduced in the fluid filmbetween surfaces which move relative to each other. As a result, theefiiciency and output of the apparatus is increased, and furthermore itis possible to rotate the rotors at twice the speed of conventionalapparatus of this type. However, this advantage can only be obtainedwith radially variable working chambers, since in apparatus in which thevolume of the working chambers is varied in axial direction, thecentrifugal forces limit the highest possible speeds of the respectiverotor.

In accordance with another feature of the invention, an axial bearingbetween control faces 61 and 62 may replace the coupling rollers 18. Thegap between control faces 61 and 62 is then determined by the distanceof the end bearings 19 and 20, the axial lengths of rotors 2 and 3, andthe axial thickness of the respective bearings. It is consequentlypossible to exactly determine the width of the gaps, under considerationof thermal expansion and contraction which can be compensated byselecting suitable materials for the parts. This construction of theinvention is a particularly simple and reliable way of determining thewidth of the gaps between the control faces.

When the spacing means 60, 18 between the control faces 61 and 62 areomitted, and the same slide on each other, the exact axial positions ofthe rotors can be determined by the axial distance between the endbearings 19 and 20, and by the actual length of the rotors 2 and 3.

In the illustrated embodiment, the bearing means between the controlfaces 61 and 62 is constructed as a ball bearing 18 whose cage means arepart of control disc 60, or radially project from the same so that therespective rollers or balls roll on control faces 61 and 62. Theillustrated arrangement efiects running of control disc 60 at a medianspeed between the rotary speeds of rotors 2 and 3, but the rollers alsodetermine the axial spacing of the control faces 61 and 62. When thewidth of the gaps between control disc 60 and control faces 61 and 62 iscalculated, the deformation of the rolls and of the surfaces engaged bythe same due to axial pressure must be considered.

While the axial bearings 18, 19 and 20 are shown to be roller bearings,it is possible to substitute hydrostatic, or hydrodynamic thrustbearings or axial bearings for the same. Since bearings of this type areknown, they are not illustrated. The use of bearings of this type hasthe advantage that the axial length and distances of the cooperatingparts and surfaces can be easily determined.

In apparatus in which due to thermal fluctuations, or due to deformationby pressure, the gap between cooperating control faces may become toowide, it is preferred to provide axially effective pressure means forurging at least one rotor towards the other. The drawing shows an axialbore 42 in part 22 of rotor 3 into which through conduit 43 in member21, and conduit 43' in rotor 3, a fluid is guided from an adjacentworking chamber 5. An axially moving pressure piston 24 is located inthe bore 42, provided with sealing means 25, and abutting the rotarydisc 23 which is freely rotatable and located between rotor 3 and ballbearing 20 which is located between rotary disc 23 and the end cover 34of the stator. The end bearing of rotor 3 consequently includes rotarydisc 23 and roller bearing 20. The fluid pressure in bore or bores 42cannot displace pressure member 24 which abuts disc 23, so that rotor 3is urged to move toward rotor 2 and the gaps between confronting controlfaces 61 and 62 and control disc 60 become a minimum. The axial reactionforce is transmitted by pressure member 24, disc 23, and roller bearing20 to the stator cover plate 34.

In accordance with the invention, the pressure member 24 is normallycompletely retracted into the bore 42 and does not project in axialdirection from rotor 3 so that disc 23 can be in contact with the outerend face of rotor 3. Only when a noticeable change of the axial distancebetween the end bearings 19 and 20 takes place, for example at highpressure, or due to deformations, does pressure member 24 project out ofbore 42, abutting rotary disc 23.

The regulator 35 serves in a well known manner to adjust the effectivevolume of the radial chambers 4 of rotor 2 so that a speed variation isobtained for a hydrostatic transmission, and a discharge volumeregulation is obtained for the pump unit to which rotor 2 belongs.Conduits 44 and 46 are provided in he pistons 7 for supplying fluid fromthe working chambers to the slide faces of the slide shoes 9 which slideon the inner surface of the eccentric ring 10. Needle bearings 14 mountring in the ring-shaped portion of regulating member 35.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types offluid handling devices differing from the types described above.

While the invention has been illustrated and described as embodied in ahydrostatic transmission including two adjacent rotors it is notintended to be limited to the details shown, since various modificationsand structural changes may be made without departing in any way from thespirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims.

Iclaim:

l. Fluid handling device with radially variable working chambers,comprising stator means having confronting inner stator end faces spaceda predetermined axial distance; first and second rotor means supportedon said stator means in axially adjacent positions for rotation about acommon axis perpendicular to said stator end faces, each rotor meansbeing formed with working chambers, and having fluid displacing elementslocated in said working chambers for radial movement, said fluiddisplacing elements being operated by said stator means to reciprocatein said working chambers in radial direction for varying the volume ofthe same during rotation of the respective rotor means, said first andsecond rotor means having first and second outer rotor end faces facingin opposite axial directions and located adjacent said inner stator endfaces, respectively, parallel with the same, and fust and second innercontrol faces transverse to said axis confronting each other and forminga gap; conduit means connecting said working chambers of said first andsecond rotor means through said gap and said control faces with eachother; and first and second bearing means having a predetermined axialthickness constant also in radial direction and spacing said outer rotorend faces, respectively, in axial direction from said inner stator endfaces fro determining the axial positions of said first and second rotormeans for maintaining a desired axial thickness of said gap.

2. Fluid handling device as claimed in claim 1 comprising spacing meanslocated in said gap between said first and second control surfaces andincluding roller bearing means rotatable about radially extending axes,and having roller means in rolling contact with said first and secondcontrol faces and having the same constant axial width as said gap.

3. Fluid handling device as claimed in claim 1 comprising spacing meansrotatable in said gap and including third bearing means having the sameconstant axial width as said gap and being in contact with said firstand second inner control faces.

4. Fluid handling device with radially variable working chambers,comprising stator means; first and second rotor means supported on saidstator means for rotation about a common axis in axially adjacentpositions, each rotor means being formed with working chambers, andhaving fluid displacing elements located in said working chambers forradial movement, said fluid displacing elements being operated by saidstator means to reciprocate in said working chambers in radial directionfor varying the volume of the same during rotation of the respectiverotor means, said first and second rotor means having first and secondouter end faces facing in opposite axial directions, and first andsecond inner control faces transverse to said axis confronting eachother and forming a gap; conduit means connecting said working chambersof said first and second rotor means through said gap and said controlfaces with each other; first and second bearing means mounted on saidstator means and supporting said outer end faces, respectively, in axialdirection for determining the axial positions of said first and secondrotor means; a control disc between said first and second inner controlfaces, and being freely rotatable about said axis; cage means mounted onsaid disc projecting from the periphery of the same in radial direction;and coupling roller means mounted in said cage means and being inrolling contact with said first and second inner control faces so thatsaid control disc rotates at a speed intermediate the speeds of saidfirst and second rotor means.

5. Fluid handling device with radially variable working chambers,comprising stator means; first and second rotor means supported on saidstator means for rotation about a common axis in axially adjacentpositions, each rotor means being formed with working chambers, andhaving fluid displacing elements located in said working chambers forradial movement, said fluid displacing elements being operated by saidstator means to reciprocate in said working chambers in radial directionfor varying the volume of the same during rotation of the respectiverotor means, said first and second rotor means having first and secondouter end faces facing in opposite axial directions, and first andsecond inner control faces transverse to said axis confronting eachother and forming a gap, one of said rotor means being formed with apressure chamber communicating with at least one of said workingchambers, and including a pressure member axially movable in saidpressure chamber; conduit means connecting said working chambers of saidfirst and second rotor means through said gap and said control faceswith each other; first and second bearing means mounted on said statormeans and supporting said outer end faces, respectively, in axialdirection for determining the axial positions of said first and secondrotor means, one of said bearing means including a disc mounted forrotation on said one rotor means, and an end bearing between said discand said stator means; said pressure member abutting said disc underpressure so that said one rotor means is urged in axial direction towardthe respective other rotor means whereby said gap has minimum thickness.

6. Fluid handling device as claimed in claim 1 comprising fluid pressuremeans located between at least one of said first and second bearingmeans and the respective outer end face of the respective rotor meansand urging the latter in axial direction toward the respective otherrotor means whereby said gap has a minimum thickness.

7. Fluid handling device as claimed in claim 1 comprising a thirdbearing means located in said gap and being in contact with said firstand second inner control faces; and wherein at least one of said bearingmeans includes a roller bearing having a radial axis.

8. Fluid handling device as claimed in claim 1 comprising a thirdbearing means located in said gap and being in contact with said firstand second inner control faces; and wherein at least one of said firstand second bearing means includes axially acting fluid pressure meanscommunicating with at least one of said pressure chambers.

9. Fluid handling device as claimed in claim 1 wherein said conduitmeans are fonned in said first and second rotor means.

10. Fluid handling device as claimed in claim 1, comprising an auxiliarypump mounted on said stator means surrounding a portion of one of saidrotor means and operated by the same during rotation of the same; andconduit means in said one rotor means having a port on said portion ofsaid one rotor means communicating with said auxiliary pump forconnecting said auxiliary pump with at least one of said workingchambers of said one rotor means for pumping fluid into the same duringa movement of the respective fluid displacing element causing a volumeincrease of said one working chamber.

11. Fluid handling device as claimed in claim 1 wherein one of saidrotor means has an axially projecting hub portion mounting the otherrotor means for rotation about said axis.

12. Fluid handling as claimed in claim 11 device wherein said hubportion is hollow; wherein said other rotor means has an other hubportion mounted on said hollow hub portion for rotation, and a hollowshaft end portion projecting from said other hub portion; and comprisinga shaft passing through said hollow hub portion and said hollow shaft.

1. Fluid handling device with radially variable working chambers,comprising stator means having confronting inner stator end faces spaceda predetermined axial distance; first and second rotor means supportedon said stator means in axially adjacent positions for rotation about acommon axis perpendicular to said stator end faces, each rotor meansbeing formed with working chambers, and having fluid displacing elementslocated in said working chambers for radial movement, said fluiddisplacing elements being operated by said stator means to reciprocatein said working chambers in radial direction for varying the volume ofthe same during rotation of the respective rotor means, said first andsecond rotor means having first and second outer rotor end faces facingin opposite axial directions and located adjacent said inner stator endfaces, respectively, parallel with the same, and first and second innercontrol faces transverse to said axis confronting each other and forminga gap; conduit means connecting said working chambers of said first andsecond rotor means through said gap and said control faces with eachother; and first and second bearing means having a predetermined axialthickness constant also in radial direction and spacing said outer rotorend faces, respectively, in axial direction from said inner stator endfaces fro determining the axial positions of said first and second rotormeans for maintaining a desired axial thickness of said gap.
 2. Fluidhandling device as claimed in claim 1 comprising spacing means locatedin said gap between said first and second control surfaces and includingroller bearing means rotatable about radially extending axes, and havingroller means in rolling contact with said first and second control facesand having the same constant axial width as said gap.
 3. Fluid handlingdevice as claimed in claim 1 comprising spacing means rotatable in saidgap and including third bearing means having the same constant axialwidth as said gap and being in contact with said first and second innercontrol faces.
 4. Fluid handling device with radially variable workingchambers, comprising stator means; first and second rotor meanssupported on said stator means for rotation about a common axis inaxially adjacent positions, each rotor means being formed with workingchambers, and having fluid displacing elements located in said workingchambers for radial movement, said fluid displacing elements beingoperated by said stator means to reciprocate in said working chambers inradial direction for varying the volume of the same during rotation ofthe respective rotor means, said first and second rotor means havingfirst and second outer end faces facing in opposite axial directions,and first and second inner control faces transverse to said axisconfronting each other and forming a gap; conduit means connecting saidworking chambers of said first and second rotor means through said gapand said control faces with each other; first and second bearing meansmounted on said stator means and supporting said outer end faces,respectively, in axial direction for determining the axial positions ofsaid first and second rotor means; a control disc between said first andsecond inner control faces, and being freely rotatable about said axis;cage means mounted on said disc projecting from the periphery of thesame in radial direction; and coupling roller means mounted in said cagemeans and being in rolling contact with said first and second innercontrol faces so that said control disc rotates at a speed intermediatethe speeds of said first and second rotor means.
 5. Fluid handlingdevice with radially variable working chambers, comprising stator means;first and second rotor means supported on said stator means for rotationabout a common axis in axially adjacent positions, each rotor meansbeing formed with working chambers, and having fluid displacing elementslocated in said working chambers for radial movement, said fluiddisplacing elements being operated by said stator means to reciprocatein said working chambers in radial direction for varying the volume ofthe same during rotation of the respective rotor means, said first andsecond rotor means having first and second outer end faces facing inopposite axial directions, and first and second inner control facestransverse to said axis confronting each other and forming a gap, one ofsaid rotor means being formed with a pressure chamber communicating withat least one of said working chambers, and including a pressure memberaxially movable in said pressure chamber; conduit means connecting saidworking chambers of said first and second rotor means through said gapand said control faces with each other; first and second bearing meansmounted on said stator means and supporting said outer end faces,respectively, in axial direction for determining the axial positions ofsaid first and second rotor means, one of said bearing means including adisc mounted for rotation on said one rotor means, and an end bearingbetween said disc and said stator means; said pressure member abuttingsaid disc under pressure so that said one rotor means is urged in axialdirection toward the respective other rotor means whereby said gap hasminimum thickness.
 6. Fluid handling device as claimed in claim 1comprising fluid pressure means located between at least one of saidfirst and second bearing means and the respective outer end face of therespective rotor means and urging the latter in axial direction towardthe respective other rotor means whereby said gap has a minimumthickness.
 7. Fluid handling device as claimed in claim 1 comprising athird bearing means located in said gap and being in contact with saidfirst and second inner control faces; and wherein at least one of saidbearing means includes a roller bearing having a radial axis.
 8. Fluidhandling device as claimed in claim 1 comprising a third bearing meanslocated in said gap and being in contact with said first and secondinner control faces; and wherein at least one of said first and secondbearing means includes axially acting fluid pressure means communicatingwith at least one of said pressure chambers.
 9. Fluid handling device asclaimed in claim 1 wherein said conduit means are formed in said firstand second rotor means.
 10. Fluid handling device as claimed in claim 1,comprising an auxiliary pump mounted on said stator means surrounding aportion of one of said rotor means and operated by the same duringrotation of the same; and conduit means in said one rotor means having aport on said portion of said one rotor means communicating wiTh saidauxiliary pump for connecting said auxiliary pump with at least one ofsaid working chambers of said one rotor means for pumping fluid into thesame during a movement of the respective fluid displacing elementcausing a volume increase of said one working chamber.
 11. Fluidhandling device as claimed in claim 1 wherein one of said rotor meanshas an axially projecting hub portion mounting the other rotor means forrotation about said axis.
 12. Fluid handling as claimed in claim 11device wherein said hub portion is hollow; wherein said other rotormeans has an other hub portion mounted on said hollow hub portion forrotation, and a hollow shaft end portion projecting from said other hubportion; and comprising a shaft passing through said hollow hub portionand said hollow shaft.